Research on Optimization and Application of LOD Algorithm in Virtual Reality Visualization of Terrain

2014 ◽  
Vol 687-691 ◽  
pp. 1258-1261
Author(s):  
Jing Sun ◽  
Hong Tao Wang
Keyword(s):  
Virtual Reality ◽  
Real Time ◽  
Large Scale ◽  
Design Work ◽  
Terrain Rendering ◽  
Key Technology ◽  
Progressive Mesh ◽  
Key Technologies ◽  
Methods And Techniques ◽  
Visibility Culling

With the development of computer graphics, real-time rendering-based VF: technology has been applied in more and more fields. LOD is the key technology in large-scale terrain rendering. In this paper, the basic concept of LOD is introduced briefly and some algorithms of LOD in use are mentioned and analyzed; secondly as one of algorithms of LOD, View-Dependent Progressive Mesh algorithm is studied and improved, the result of implementing the large-scale terrain’s LOD by using VDPM is presented. There are key technologies in LOD Large-scale terrain real-time rendering are researched. Relative technologies are presented such as: LOD of the terrain, visibility culling, and cracks eliminate, view-dependent refine, LOD error, technologies of texture etc. Using LOD technology, VR system can greatly reduce the; number of polygons produced in real-time rendering procedure. Finally, we do experimental design work based on the methods and techniques presented by this paper.

scholarly journals Prevention of Mountain Disasters and Maintenance of Residential Area through Real-Time Terrain Rendering

2021 ◽  
Vol 13 (5) ◽  
pp. 2950
Author(s):  
Su-Kyung Sung ◽  
Eun-Seok Lee ◽  
Byeong-Seok Shin
Keyword(s):  
Real Time ◽  
Graphics Processing Units ◽  
High Speed ◽  
Large Scale ◽  
Civil Engineering ◽  
Three Dimensional ◽  
Sampled Data ◽  
Residential Areas ◽  
Terrain Rendering ◽  
Mountain Disasters

Climate change increases the frequency of localized heavy rains and typhoons. As a result, mountain disasters, such as landslides and earthworks, continue to occur, causing damage to roads and residential areas downstream. Moreover, large-scale civil engineering works, including dam construction, cause rapid changes in the terrain, which harm the stability of residential areas. Disasters, such as landslides and earthenware, occur extensively, and there are limitations in the field of investigation; thus, there are many studies being conducted to model terrain geometrically and to observe changes in terrain according to external factors. However, conventional topography methods are expressed in a way that can only be interpreted by people with specialized knowledge. Therefore, there is a lack of consideration for three-dimensional visualization that helps non-experts understand. We need a way to express changes in terrain in real time and to make it intuitive for non-experts to understand. In conventional height-based terrain modeling and simulation, there is a problem in which some of the sampled data are irregularly distorted and do not show the exact terrain shape. The proposed method utilizes a hierarchical vertex cohesion map to correct inaccurately modeled terrain caused by uniform height sampling, and to compensate for geometric errors using Hausdorff distances, while not considering only the elevation difference of the terrain. The mesh reconstruction, which triangulates the three-vertex placed at each location and makes it the smallest unit of 3D model data, can be done at high speed on graphics processing units (GPUs). Our experiments confirm that it is possible to express changes in terrain accurately and quickly compared with existing methods. These functions can improve the sustainability of residential spaces by predicting the damage caused by mountainous disasters or civil engineering works around the city and make it easy for non-experts to understand.

A POINT-BASED ASYNCHRONOUS REMOTE VISUALIZATION FRAMEWORK FOR REAL-TIME VIRTUAL REALITY

2008 ◽  
Vol 08 (02) ◽  
pp. 189-207
Author(s):  
JINGHUA GE ◽  
DANIEL J. SANDIN ◽  
TOM PETERKA ◽  
ROBERT KOOIMA ◽  
JAVIER I. GIRADO ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Real Time ◽  
High Speed ◽  
Large Scale ◽  
Julia Set ◽  
Remote Visualization ◽  
Space Partition ◽  
Original Dataset ◽  
View Reconstruction ◽  
Occlusion Culling

High speed interactive virtual reality (VR) exploration of scientific datasets is a challenge when the visualization is computationally expensive. This paper presents a point-based remote visualization pipeline for real-time virtual reality (VR) with asynchronous client-server coupling. Steered by the client-end frustum request, the remote server samples the original dataset into 3D point samples and sends them back to the client for view updating. From every view updating frame, the client incrementally builds up a point-based geometry under an octree-based space partition hierarchy. At every view-reconstruction frame, the client continuously splats the available points onto the screen with efficient occlusion culling and view-dependent level of detail (LOD) control. An experimental visualization framework with a server-end computer cluster and a client-end head-tracked autostereo VR desktop display is used to visualize large-scale mesh datasets and ray-traced 4D Julia set datasets. The overall performance of the VR view reconstruction is about 15 fps and independent of the original dataset complexity.

scholarly journals Language Education in the Age of Globalization and Innovation

2019 ◽  
Vol 71 ◽  
pp. 05010
Author(s):  
V. Dobrova ◽  
P. Labzina ◽  
N. Ageenko ◽  
S. Menshenina
Keyword(s):  
Virtual Reality ◽  
Real Time ◽  
3D Modeling ◽  
Language Education ◽  
Innovative Technology ◽  
Language Program ◽  
The Real ◽  
New Methods ◽  
Methods And Techniques ◽  
Frame Method

Globalization and innovation have recently resulted in the extensive use of the latest technological products practically everywhere, and in education especially. Various technologies are now employed in different spheres of education. Virtual Reality (VR) is a global innovative technology with great potentials and enormous pedagogical possibilities that offers new methods and techniques for education. The main features of it are visibility, security, involvement, presence and focusing. It enables to combine the computer-generated virtual information and the real environment in real time. The presented VR language program is based on the concept of 3D modeling and semantic frame method.

Visualising large-scale geodynamic simulations: How to Dive into Earth's Mantle with Virtual Reality

2020 ◽  
Author(s):  
Markus Wiedemann ◽  
Bernhard S.A. Schuberth ◽  
Lorenzo Colli ◽  
Hans-Peter Bunge ◽  
Dieter Kranzlmüller
Keyword(s):  
Virtual Reality ◽  
Real Time ◽  
High Performance ◽  
Large Scale ◽  
Large Data ◽  
Optimization Techniques ◽  
Physical Parameters ◽  
Mantle Flow ◽  
Data Set ◽  
Precise Knowledge

<p>Precise knowledge of the forces acting at the base of tectonic plates is of fundamental importance, but models of mantle dynamics are still often qualitative in nature to date. One particular problem is that we cannot access the deep interior of our planet and can therefore not make direct in situ measurements of the relevant physical parameters. Fortunately, modern software and powerful high-performance computing infrastructures allow us to generate complex three-dimensional models of the time evolution of mantle flow through large-scale numerical simulations.</p><p>In this project, we aim at visualizing the resulting convective patterns that occur thousands of kilometres below our feet and to make them "accessible" using high-end virtual reality techniques.</p><p>Models with several hundred million grid cells are nowadays possible using the modern supercomputing facilities, such as those available at the Leibniz Supercomputing Centre. These models provide quantitative estimates on the inaccessible parameters, such as buoyancy and temperature, as well as predictions of the associated gravity field and seismic wavefield that can be tested against Earth observations.</p><p>3-D visualizations of the computed physical parameters allow us to inspect the models such as if one were actually travelling down into the Earth. This way, convective processes that occur thousands of kilometres below our feet are virtually accessible by combining the simulations with high-end VR techniques.</p><p>The large data set used here poses severe challenges for real time visualization, because it cannot fit into graphics memory, while requiring rendering with strict deadlines. This raises the necessity to balance the amount of displayed data versus the time needed for rendering it.</p><p>As a solution, we introduce a rendering framework and describe our workflow that allows us to visualize this geoscientific dataset. Our example exceeds 16 TByte in size, which is beyond the capabilities of most visualization tools. To display this dataset in real-time, we reduce and declutter the dataset through isosurfacing and mesh optimization techniques.</p><p>Our rendering framework relies on multithreading and data decoupling mechanisms that allow to upload data to graphics memory while maintaining high frame rates. The final visualization application can be executed in a CAVE installation as well as on head mounted displays such as the HTC Vive or Oculus Rift. The latter devices will allow for viewing our example on-site at the EGU conference.</p>

Augmented Reality on Longwall Face for Unmanned Mining

2010 ◽  
Vol 40-41 ◽  
pp. 388-391 ◽  
Author(s):  
Shou Xiang Zhang
Keyword(s):  
Virtual Reality ◽  
Theoretical Model ◽  
Augmented Reality ◽  
Real Time ◽  
Longwall Face ◽  
3D Registration ◽  
Mining Technology ◽  
Key Technology ◽  
The Real ◽  
Alpha Channel

An unmanned mining technology for the fully mechanized longwall face automation production is proposed and studied. The essential technology will bring the longwall face production into visualization through the Virtual Reality (VR) and Augmented Reality (AR) union. Based on the visual theoretical model of the longwall face, the combination of virtual and reality, the real-time interactive and the 3D registration function were realized. The Key technology and Alpha channel are used to the combination of the real long wall face and the virtual user.

scholarly journals Intangible Narratives; An investigation on immersive architectural   visualisation in VR.

2021 ◽  
Author(s):  
◽  
Kar Wing Leung
Keyword(s):  
Virtual Reality ◽  
Real Time ◽  
Virtual Environment ◽  
Google Earth ◽  
Virtual Architecture ◽  
Methods And Techniques ◽  
Current Context ◽  
Tool Set

<p>Within the current context of digital architectural construction and immersive representation exists a problem of ‘ocularcentrism’ as defined by Pallasmaa. Recent immersive developments such as Google Earth VR, or Realities.io, focus primarily in working within the tangible experience, purely emphasising on geometric forms and physical artefacts. They largely ignore the more experiential and intangible qualities of space, which are crucial elements in a real embodied physical experience of architecture. Phenomenologists such as Pallasmaa, Holl, and Zumthor expand on this, identifying that architecture clearly exists as something beyond just the tangible. Architecture fundamentally is an experiential and spatial art, incorporating not just the geometric sense of space but also aspects of the intangible such as sound, movement, lighting and interaction. As a result of this tangible-bias, virtual-reality’s current use within architecture as an immersive medium is largely limited. Most developments can be described as ‘an immersive virtual photograph’ of architecture rather than an experience of one.  This research is a response to studies that directly address the problem of ‘ocularcentrism’ while also exploring the methods and techniques that can translate intangible qualities into virtual architecture. Utilising a Real-Time Virtual Environment (RTVE) and Virtual Reality (VR) tool set, this paper virtually reconstructs the case study of the Kowloon Walled City. It proposes a novel working methodology for immersive architectural visualisation with VR and adds to the on-going research in the field of phenomenology within architecture.</p>

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